The Claim

Fewer than 10% of obese adults who initiate a protein-sparing modified fast achieve and maintain at least 15% weight loss five years after initiation.

Source: The Effect of Starting the Protein-Sparing Modified Fast on Weight Change over 5 years

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
59score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

Among obese adults who start a protein-sparing modified fast, fewer than 10% keep off at least 15% of their body weight five years later.

See the scientific wording

Fewer than 10% of obese adults who initiate the protein-sparing modified fast maintain ≥15% weight loss after five years, indicating that durable, clinically significant weight loss is rare regardless of diet choice.

Why this might work

When a person loses a lot of weight, the body slows down metabolism, increases hunger signals, and becomes less responsive to hormones that signal fullness. This makes it harder to keep eating less and burn fewer calories, so weight returns.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: The Effect of Starting the Protein-Sparing Modified Fast on Weight Change over 5 years

    The study found that less than 10% of obese people who tried the PSMF diet lost 15% or more of their weight and kept it off for five years — and the same was true for people on other diets. So, no matter which diet you pick, it’s very hard to keep off a lot of weight long-term.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.